I read that in 1828 only 15,000 or so of these were minted. Does anyone know the value about these coins?
2006 Edition of Krause 1800's coinage lists the mintage at 16,000, with F price of $15.00 and VF 1t $35.00. Once again, your price depends on grade. Post a picture if you can. As a personal experience side-note, these sell for about 10-15 dollars max at circulated grades, on average. Which only means that's what I've seen that date range selling for. Not what someone might pay for it. Not a bad coin to have at all however, I'm missing it in my G.B. collection!
According to Spink, the 1828 Sixpence is £10 in Fine, £45 in VF, £175 in EF and £400 in Unc. The most valuable in the George IV series (George VII doesn't exist yet, or at least he won't exist in that form until Prince Charles assumes the throne and with it his intended regal name) is the 1826, which is £600 in Unc, which isn't the most ridiculous price on the planet tbh..... I don't know if the mintage figure you quote is correct, but mintage figures won't tell you everything about the price, or even about how rare it is. For example, the London Mint 1917 Sovereigns had a mintage in excess of a million, yet it is one of the most notoriously rare sovereigns in the entire series, with a Marsh rating of R5, because almost all of them were shipped off to the US and melted down to pay for war materials.....